1. Field of the Invention
The invention relates to an apparatus for actuating a deep-sea drill.
2. Description of Related Prior Art
U.S. Pat. No. 5,662,335 discloses a pressure balanced bellows seal. The bellows seal includes a seal bellows assembly which is operatively and sealingly attached to the valve stem, a counterbellows assembly which is substantially concentric with the seal bellows assembly, a midplate which operatively joins the seal bellows assembly and the counterbellows assembly in an end-to-end arrangement and an inert fluid within the cavity formed by the seal bellows assembly and the counterbellows assembly and which is moveable therebetween to compensate for volumetric changes resulting from the axial movement of the valve stem. The inert fluid balances the pressure of the process fluid and distributes it substantially uniformly against the seal bellows assembly and the counterbellows assembly thus substantially eliminating any pressure stresses within the bellows assemblies.
U.S. Pub. No. 2013/0032226 discloses a GAS LIFT VALVE HAVING EDGE-WELDED BELLOWS AND CAPTIVE SLIDING SEAL. A gas lift apparatus has a gas lift valve that disposes in a mandrel. A housing of the valve has a chamber, and a seat disposes between the inlet and outlet. A piston movably disposed in the housing has one end exposed to the chamber. A distal end can selectively seal with the seat to close the valve. A first edge-welded bellows disposed on the piston separates the inlet and chamber pressures and can fully compress to a stacked height when the distal end of the piston seals with the seat. A dynamic seal can be achieved at closing by using a captive sliding seal between the piston's distal end and the seat. A second edge-welded bellows can also be disposed on the piston, and the two bellows can operate in tandem. Oil filing the interiors and the passage can move from one bellows to the other to transfer the pressure differential between the inlet and the chamber pressures. The second bellows fully compresses to a stacked height and stops opening of the valve.